The present invention relates generally to off-road motor vehicles, such as utility or recreational vehicles, and more particularly, to a steering mechanism that permits a decreased turning radius for the vehicle and enhanced steering precision.
Small off-road vehicles such as utility or recreational vehicles are becoming popular for recreational and other general purpose off-road usage. Such utility vehicles can be found in U.S. Pat. No. 4,706,770. These utility vehicles have found usage on golf courses and at sporting events, and are particularly adaptable for utilization on a farm. This type of flexibility in the wide variety of uses necessitates a vehicle that is highly flexible, highly maneuverable and the like. This demands a vehicle that will afford a high degree maneuverability and ease of steering.
Steering characteristics of known utility vehicles provide poor turning performance. Known utility vehicles have turning clearance circles having a diameter greater than twenty-one feet. The use of independent front wheel suspension mechanisms on known utility vehicles, coupled with the mounting of the rack and pinion systems on the frame of the vehicle, introduces minor king pin rotations as the steering tires ride over ground undulations. Such construction reduces steering precision and can accelerate the wear of the tires on the steering axle.
Improved steering characteristics could be provided through an adaptation of the compound steering mechanism developed for agricultural tractors, as is shown in U.S. Pat. No. 5,129,477, issued to Joseph C. Hurlburt on Jul. 14, 1992. The adaptation of such a mechanism would require a lengthening of the wheel base of the utility vehicle. Lengthening of the wheel base results in increased shipping size and increased dealer set up labor, as well as increased manufacturing costs for the utility vehicle.
Placing a load on the utility vehicle typically results in a variation in the steering performance of known utility vehicles. For example, one known embodiment having a front steering axle, a rear drive axle, and a middle drive axle carries the load placed on the vehicle on the middle and rear axles, resulting in less weight on the steering axle and a reduction in maneuverability. Accordingly, known utility vehicle construction results in a significant influence on the steering performance by the load carried on the vehicle. Preferably, loads should not change the steering characteristics for any vehicle.
It is therefor desirable to provide an enhanced steering mechanism for utility and recreational vehicles that overcomes the disadvantages of the known prior art utility vehicles.
Accordingly, an important object of the present invention is to provide a steering mechanism that overcomes the above mentioned problems encountered in the prior art.
It is another object of this invention to provide a steering mechanism that enhances steering precision for utility vehicles.
It is a further object of this invention to provide a steering mechanism that decreases the turning radius for an off-road vehicle.
It is a further object of this invention that the inner clearance diameter for an off-road vehicle is reduced.
It is another object of this invention that steering angles are increased.
It is a feature of this invention to add a tie rod and two bell cranks to the steering system of a utility vehicle.
It is another feature of this invention that the enhanced steering geometry allows the steering angles to be increased to approximately 70xc2x0 for the inner wheel.
It is an advantage of this invention that maneuverability is greatly increased.
It is a another advantage of this invention that oscillation induced steering is eliminated.
It is a further object of this invention to provide a steering mechanism for an off-road vehicle that is durable in construction, inexpensive to manufacture, carefree in maintenance, easy to assemble, and simple and effective in use.
These and other objects, features, and advantages are accomplished according to the present invention by providing a utility vehicle having a steering mechanism that increases the turning angle of the steered wheels without requiring a lengthening of the wheel base of the vehicle. The steering mechanism includes a pair of bell cranks pivotally mounted to the steering axle of the vehicle. A tie rod extends between the two bell cranks to effect coordinated pivotal movement therebetween. A rack and pinion mechanism transfers manipulation of the operator""s steering wheel to move the rack connected to the first bell crank and cause pivotal movement thereof. Each bell crank is associated with a steering link connected thereto at a connection point which moves on an arc centered on the respective pivot of the bell crank. The connection point moves forwardly with respect to the inner steered wheel to permit the steering arm of the inner steered wheel to rotate to an orientation that is substantially transverse to provide an enhanced turning angle for the inner steered wheel.
The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows, in conjunction with the accompanying sheets of drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention.